With the help of high technology, more a

问题选择题

With the help of high technology, more and more new substances ___in the past few years.

A．discovered

B．have discovered

C．had been discovered

D．have been discovered

答案

答案：D

题目分析：考查时态。根据时间状语in the past few years,说明使用现在完成时。根据句意说明使用被动形式。句意：因为有高科技的帮助，早最近几年中，越来越多的物质已经被发现了。故D正确。

点评：对于时态的考查要从关键词着手，也要在语境中进行。